This project intends to define the hamster model of large intestinal cancer and of mammary cancer as induced by oral 3- methylcholanthrene (MC) and to study chemical carcinogenesis by other routes (subcutaneous) and other carcinogens in inbred Syrian hamsters. This will include the definition of the genetic background of susceptibility and resistance. The eventual aim is the development of chemically induced experimental cancers in Syrian hamsters of controlled genetic background that will serve as models to detect environmental cancer-causing agents relevant to the human disease.